Chandra HETG Observations of the Colliding Stellar Wind System WR 147

TL;DR

This study analyzes deep Chandra HETG X-ray observations of the WR 147 binary system, revealing details about the origin of X-ray emissions and the dynamics of colliding stellar winds.

Contribution

It provides the first detailed spectral analysis of WR 147's double X-ray source, clarifying the physical origins of the emissions and the system's wind interactions.

Findings

Northern X-ray source is associated with colliding stellar winds.

X-ray emitting region is not close enough to the stars to be UV-affected.

Southern X-ray source likely from wind shocking onto a close companion.

Abstract

We present an extended analysis of deep Chandra HETG observations of the WR+OB binary system WR 147 that was resolved into a double X-ray source (Zhekov & Park, 2010, ApJ, 709, L119). Our analysis of the profiles of strong emission lines shows that their centroids are blue-shifted in the spectrum of the northern X-ray source. We find no suppressed forbidden line in the He-like triplets which indicates that the X-ray emitting region is not located near enough to the stars in the binary system to be significantly affected by their UV radiation. The most likely physical picture that emerges from the entire set of HETG data suggests that the northern X-ray source can be associated with the colliding stellar wind region in the wide WR+OB binary system, while the X-rays of its southern counterpart, the WN8 star, are result from stellar wind shocking onto a close companion (a hypothesized third star in the system).